Epilogue

Let’s take a moment to explain why
Kiryuu Mizuha was actually wearing those pure white panties at that
moment. You can just call this the viewpoint of Cinderella.

She had taken back the pure white pair
of panties from Keiki’s room. Now, of course, she would have to try
her best to hide those panties from him. And where would the safest
place actually be?

Normally, she could keep them
relatively safe in her own room. However, Cinderella herself stole
those exact same panties from Keiki’s room. She herself knew more
than anyone that one own’s room wasn’t actually the safest place.

Then what should she do? The answer was
simple. She should just keep them with her at all times.

When the season changes to summer, it’s
not weird for female high school students to keep an extra pair of
panties. A girl’s panties were small and compact, so it wasn’t
very difficult to keep a spare in her beg.

And that was what Keiki was aiming for.

He invited everyone out on this school
day beforehand — except Mizuha. Of course, there was a reason that
he didn’t tell her the destination, too. Just like the surprise
swimsuit, all of it had been planned by Keiki. All of it was in order
to make her wear Cinderella’s panties.

After playing in the pool, she would of
course change back into her normal uniform. But there was no way that
she could’ve prepared another pair of panties — except the one
she had been hiding in her bag this whole time, of course.

Now she had two choices.

The first choice was to put on the used
pair of panties she had been wearing until that point.

The second choice was to wear
Cinderella’s panties, which she hadn’t prepared beforehand.

Now, what was one of Mizuha’s
particular personality traits?

Yes, she was a clean freak. She
would’ve hated the feeling of wearing those used panties again.
Even the boy Keiki always avoided wearing the same pair of underwear
twice in the same day. After all, during this humid summer weather,
sweating was a normal thing to do.

And with all this in mind, Keiki
deduced that she must be wearing Cinderella’s panties today.

“So everything today was planned in
order to make me wear these panties, I see.”

“Otherwise I wouldn’t have any
definite proof, after all.”

On the stairs inside the pool building,
Cinderella asked the prince a single question.

“How did you know that it was me?”

“Because of this picture.”

What Keiki took out of his pocket was
the single picture that Koharu had taken. Though it was originally
taken because of Shouma, it clearly showed Mizuha walking in the
front yard of the school grounds.

“This photo was taken on the day that
I found the love letter. The photo was taken around 7.50pm. Having
finished everything in the clubroom, I was already on my way home at
that time.”

Yes, this single photo had turned the
key and revealed Cinderella’s identity.

“That day, the cleaning operation
ended around 5pm. All of the other members of that operation were
supposed to have gone home already. So why was it that Mizuha was
still at school at that time?”

At the time, Mizuha had said that she
wanted to go home to take a shower. However, it was actually Keiki
who had gotten home first. And since her older brother was too busy
thinking about the love letter, he didn’t realize that Mizuha
hadn’t gotten home yet.

“Thinking about it, there’s only
one reason. Sayuki-senpai wasn’t the last person in the room. You
put the letter on the table, hid yourself in the locker, and escaped
from inside the room after I went home.”

The last person who left the room
wasn’t Sayuki, but Mizuha. She had just lied about it, in order to
hide the truth. And since she lived in the same house as Keiki, it
was rather simple for her to steal the panties from his room.

“Of course I didn’t search inside
your room. I never saw you as a Cinderella candidate, after all.”

It was just like the math problem he
had helped Yuika with before. If you can’t get to the answer, then
the whole premise is wrong to begin with. He had decided upon the
fact that his little sister Kiryuu Mizuha couldn’t be Cinderella,
and that’s why he was unable to find her until now.

“Everything you said is correct,
Nii-san. I left the love letter there. I just thought that my
feelings had to reach Nii-san.”

She was talking about her feelings on
that fateful day.

“But at the same time, I was scared.
About telling Nii-san how I feel. I was scared that we couldn’t go
back to being close siblings like this.”

“…So that’s why you didn’t
write your name on the letter?”

“I wonder? Maybe I wanted you to
chase me. Maybe I wanted to be found by the boy that I like.”

“………”

Keiki couldn’t say anything in
response.

“…Hey, Nii-san?”

Her voice sounded out, as calming as a
gentle rain.

“I like you.”

And what came out of her mouth was the
exact same confession that Keiki had found in the love letter. Even
the thick-headed Keiki would understand this. Mizuha liked Keiki, and
not as her older brother, but as a man.

“When you’re kind to me, when you
spoil me, when you always give it your all. Even when you’re
clumsy. I like everything about you.”

With these sweet, oh so sweet feelings
flowing out of her mouth, she continued to gaze directly at Keiki.

“Nii-san…”

It was the expression of a young maiden
in love. As he was looked at with watery eyes, Keiki couldn’t stand
it anymore and averted his eyes.

Uwaaah… what is this…? This is
really hard to reject, though…

There was actually another goal for
today besides concretely identifying Cinderella. In order to answer
this young maiden’s feelings, in order to reject her, he had
brought her to this place.

Once he figured out Cinderella’s
identity, the answer was as clear as day for Keiki. Of course, he
loved Mizuha, and he treasured her. However, that was only a love for
a member of his family. Nothing more, nothing less. No matter how
strong their feelings for each other might be, going out with his
blood-related sister was ethically immoral. He couldn’t look at her
as a member of the opposite sex, and he couldn’t develop any
romantic feelings for her.

—This was Keiki’s decision.

“I’m really happy about Mizuha’s
feelings… But, after all… we are…”

As he was assaulted with a feeling of
guilt, the words wouldn’t come out of the prince’s mouth. He
didn’t think that turning down a person could be this painful.

“…Since we’re siblings, it’s
wrong for us to be in love with each other?”

As Mizuha spoke aloud the feelings that
Keiki felt, he could only nod.

“…Yeah, I think that it’s wrong.”

A younger sister having romantic
feelings for her older brother wasn’t something normal. Sure, in
their childhood days, they had made stories up about marrying each
other in the future. But sadly, back then they were not full-fledged
high school students. He needed to turn her down so that she could
experience normal love, with a normal boy.

“………It’s not wrong at all.”

“Mizuha…?”

What called him back was a cold voice,
deep like the ocean, and it sounded like it was close to tears.

“Nii-san? We’re siblings of the
same age, right?”

“Nnn? Ah, yeah. You’re right, but…”

Currently, the ribbon that Mizuha was
wearing was a beige color. Just like Mao and Ayano, she was a
second-year student. That was the reason that Yuika had called her
“Mizuha-senpai.” She was the same age as her older brother. But
Keiki couldn’t quite understand the reasoning for why she had
brought that up so suddenly.

“When was your birthday again,
Nii-san?”

“The 11th of October.”

“Yeah.
I was born on the 3rd of March.”

“And what’s your point?”

“Don’t you think that it’s weird?
Even though we were born in the same year, there’s only 5 months
between our birth dates.”

“Eh? Isn’t that just because our
old man worked really hard?”

“Even with hard work, it’s still
impossible. You paid attention in sex ed, right? You know that it
takes about ten months of pregnancy until the baby is born.”

“………”

He remembered hearing about that.

And, that meant that, if they really
were siblings of the same age, then there should be more than ten
months between their birth dates, but it was only a mere five for
Keiki and Mizuha. Until now, Keiki hadn’t thought about that at
all—

“……Eh? But… wait… that means…
huh? What does that…”

But now that he was, his heart was
beating so fast that it started to hurt.

“Nii-san…”

And while Keiki was completely frozen
in shock, Mizuha slowly drew closer. Maybe it was because of the
pool, but she somehow had a different smell to her than usual. And,
the girl slowly opened her mouth—

“I also have to apologize in advance,
okay?”

“Eh…?”

Before he had even realized it, it was
already too late. While the setting sun illuminated the stairway in a
red hue, their lips overlapped.

“—, —.

He felt his heart almost leap out of
his chest, and the blood rushed to his head. A girl’s lips were
unbelievably soft. Combining that with the abnormal situation of
kissing his actual little sister, his head couldn’t keep up. In
this state, they had a long, long kiss. However, this one kiss
completely broke their sibling relationship.

After their lips finally departed,
Keiki could only stare blankly at Mizuha, who softly opened her
mouth.